Mangrove R. Mucronata Sebagai Sampel Untuk Penelitian Daya Hambat Terhadap Bakteri Karena Sejak Beberapa Abad Yang Lalu, Masyarakat Pesisir Di Berbagai Tempat Di Indonesia Secara Tradisional Telah Memanfaatkan Jenis Ini Mulai Dari Pohon Sampai Buah Sebagai Obat-Obatan. Tujuan Penelitian Ini Mengetahui Potensi Antibakteri Daun R. Mucronata Terhadap Vibrio Spp. Dari Kepiting Bakau (Scylla Serrata). Dilaksanakan Pada Bulan Agustus 2016 - Februari 2017. Proses Ekstraksi, Isolasi Dan Pengujian Zona Bening Dilakukan Di Laboratorium Fakultas Perikanan Dan Ilmu Kelautan Universitas Borneo Tarakan. Prosedur Kerja Penelitian Yaitu Persiapan Alat Dan Bahan, Pembuatan Ekstrak Daun R. Mucronata, Isolasi, Kultur Bakteri Vibrio Spp., Dan Analisis Data. Penelitian Terdiri Atas 6 Perlakuan Yaitu Kontrol Blank, Kontrol Negatif, Kontrol Positif, Konsentrasi 10%, Konsentrasi 15%, Dan Konsentrasi 20% Dengan 4 Kali Ulangan. Diameter Zona Bening Menunjukkan Bahwa Dengan Pemberian Ekstrak Etanol Daun R. Mucronata Pada Setiap Perlakuan Berbeda Nyata (P < 0.05). Diameter Zona Bening Yang Dihasilkan Pada Konsentrasi 10% Didapatkan Nilai Rata-Rata 4,87 ± 0.85 Mm, Pada Konsentrasi 15% 11,75 ± 2.02 Mm, Pada Konsentrasi 20% 20.62 ± 0.75 Mm. Sedangkan Kontrol Positif 41 ± 0.00 Mm. Namun Pada Kontrol Blank Dan Kontrol Negatif Tidak Terbentuk Zona Bening. Berdasarkan Hasil Tersebut Dapat Disimpulkan Bahwa Ada Indikasi Pemberian Ekstrak Etanol Daun R. Mucronata Dalam Menekan Aktifitas Bakteri Vibrio Spp. Yang Diuji Secara In Vitro.
Kata Kunci: Rhizophora Mucronata, Vibrio Spp., Kepiting Bakau (Scylla Serrata), In Vitro

Mangrove R. Mucronata As Samples To Study Inhibitory To Bacteria Because Since Several Centuries Ago, The Coastal Communities In Various Places In Indonesia Traditionally Have Utilized This Type From The Tree Until The Fruit As Medicines. The Purpose Of This Study To Know The Potential Antibacterial R. Mucronata Leaves Against Vibrio Spp. Of Mud Crab (Scylla Serrata). Conducted In August 2016 - February 2017. The Process Of Extraction, Isolation And Testing Of Clear Zone Conducted At The Laboratory Of The Faculty Of Fisheries And Marine Sciences University Of Borneo Tarakan. Research Work Procedure Is The Preparation Of Tools And Materials, The Manufacture Of R. Mucronata Leaf Extract, Isolation, Culture Of Vibrio Spp., And Data Analysis. The Study Consisted Of 6 Treatments, Namely Blank Control, Negative Control, Positive Control, A Concentration Of 10%, 15% Concentration, And A Concentration Of 20% With Four Replications. Diameter Of Clear Zone Indicates That The Ethanol Extract Of Leaves Of R. Mucronata At Each Treatment Were Significantly Different (P < 0.05). Diameter Of Clear Zone Produced At A Concentration Of 10% Obtained Average Value Of 4.87 ± 0.85 Mm, At A Concentration Of 15% 11.75 ± 2:02 Mm, At A Concentration Of 20% 20.62 ± 0.75 Mm, While The Positive Control 41 ± 0:00 Mm. But The Blank Control And Negative Controls Do Not Form Clear Zones. Based On These Results It Can Be Concluded That There Are Indications Of Ethanol Extract Of Leaves Of R. Mucronata In Suppressing The Activity Of Vibrio Spp. Were Tested In Vitro. Keywords: Rhizophora Mucronata, Vibrio Spp., Mangrove Crab (Scylla Serrata), In Vitro